Wheat plant height locus RHT25 encodes a PLATZ transcription factor that interacts with DELLA (RHT1).

Area of Science:

• Plant genetics and breeding
• Agronomy

Background:

• Plant height is a crucial agronomic trait influencing wheat yield.
• Gibberellic acid (GA)-insensitive RHT dwarfing alleles improved Green Revolution varieties but had drawbacks.
• There is a need for alternative GA-sensitive dwarfing genes to enhance yield potential.

Purpose of the Study:

• To identify and characterize the gene underlying the GA-sensitive dwarfing locus RHT25 in wheat.
• To investigate the function of PLATZ-A1 in plant height regulation.
• To explore the potential of PLATZ-A1 mutations for improving wheat breeding.

Main Methods:

• Gene identification and validation using genetic analysis.
• Expression analysis in stem and spike tissues.
• Functional characterization through loss-of-function mutations and overexpression.
• Protein-protein interaction studies in yeast and wheat protoplasts.

Main Results:

• The gene underlying RHT25 was identified as PLATZ-A1 (TraesCS6A02G156600).
• PLATZ-A1 encodes a PLATZ protein and is expressed in elongating stems and developing spikes.
• Loss-of-function mutations in PLATZ-A1 reduce plant height, while overexpression increases it.
• PLATZ-A1 interacts genetically and physically with RHT1, modulating DELLA's effect on plant height.
• Selected PLATZ-A1 mutations are more frequent in modern varieties, indicating positive selection.

Conclusions:

• PLATZ-A1 is the causative gene for the RHT25 locus, offering a GA-sensitive dwarfing mechanism.
• PLATZ1's interaction with DELLA pathways provides insights into plant height regulation.
• Identified PLATZ-A1 mutations are valuable for fine-tuning wheat height and developing improved varieties.
• This research opens avenues for achieving yield gains beyond the Green Revolution through targeted breeding strategies.